If you only want vaulted skulls in your flock then you would cull for that too. I dont cull on regular or vaulted skull at all , i have both in my flocks. Although i love the looks of the vaulted skull silkies ! It's so hard to determine good crests on real young birds.
Usually about 3 to 4...
This is what i look at when determining what to keep straight out of the incubator - Dark skin , nice dark eyes , 5 toes , nice toe spacing , foot feathering
I dont cull for anything else til much later on .
Fay